(a) Additional infant diagnosis of major cardiac, pulmonary, or other disease process potentially affecting respiratory status in the neonatal period (i.e., infection, meconium aspiration, pneumothorax, congenital anomaly) present during the study period. (b) Positive test of infection (e.g. blood, CSF, or urine culture; viral DFA; microscopy) drawn from infant at any point during the study period. (c) Maternal diagnosis of chorioamnionitis or other infection of the uterus or fallopian tubes at any point during hospital stay. (d) Objective clinical signs of dehydration: (i) Newborn urine output less than 2 mL/kg/hr over a twelve hour period at any point during the study period. (ii) Newborn serum sodium less than 130 mEq/L or greater than 150 mEq/L at any point during the study period. (iii) Newborn weight loss >10% of birth weight at any point during the study period.